Sapphire

Sapphire

Sapphire is a single crystal aluminum oxide (Al 2 O 3 ). It is one of the hardest materials. sapphire has good transmission characteristics over the visible, and near IR spectrum. It exhibits high mechanical strength, chemical resistance, thermal conductivity and thermal stability. It is often used as window materials in specific field such as space technology where scratch or high temperature resistance is required.

Physical Properties

 Crystal Symmetry Hexagonal System Lattice constant A a =4.75 ; c =12.97 Transparence range μm 0.18- 4.5 Density g/cm 3 3.98 Mohs hardness 9 Melting point ℃ 2030 Thermal conductivity W/m/K 0.04 Expansion coefficien 10 -6 /K 8.4 Refractive Index 1.0 m m 1.755